Manufacturing method for ni frontside sic ohmic contact

Abstract

The present description relates to a method of manufacturing a silicon carbide wafer comprising forming a semiconductor substrate comprising SiC at a surface or at least specific parts of the surface thereof; cleaning a surface area of the substrate by a hydrogen plasma atmosphere; applying nickel metal contact material on the cleaned surface area to form SiC/Ni metal stacks at the surface of or at least parts of the SiC substrate; and annealing the SiC/Ni metal stacks to form Ohmic contacts at the interface between the SiC and the nickel metal.

1 . A method of manufacturing a silicon carbide (SiC) wafer comprising:
 forming a substrate comprising SiC at one or more parts of a surface;   cleaning a surface area of the substrate by a hydrogen plasma atmosphere;   applying nickel metal contact material on the cleaned surface area to form one or more SiC/Ni metal stacks at the one or more parts of the surface; and   annealing the one or more SiC/Ni metal stacks to form Ohmic contacts at the interface between SiC of the one or more SiC/Ni metal stacks and nickel metal of the one or more SiC/Ni metal stacks.   
     
     
         2 . The method of  claim 1 , wherein the substrate comprises a front surface on or in which semiconductor elements are formed and a back surface which faces the front surface. 
     
     
         3 . The method of  claim 2 , wherein the front surface of the substrate is cleaned and contacts are formed at one or more surface areas at which SiC is directly present at the front surface of the substrate. 
     
     
         4 . The method of  claim 3 , wherein the one or more surface areas comprise at least one of one or more n-doped SiC substrates or one or more p-doped SiC substrates. 
     
     
         5 . The method of  claim 1 , wherein the cleaning of the surface area is carried out by a hydrogen plasma processing using at least one of a pure hydrogen atmosphere or an atmosphere comprising hydrogen in admixture with at least one of a carrier or inert gas. 
     
     
         6 . The method of  claim 1 , wherein the nickel metal is applied by a sputtering process. 
     
     
         7 . The method of  claim 1 , wherein the nickel metal is applied by a vapor deposition process. 
     
     
         8 . The method of  claim 1 , wherein the annealing comprises a rapid thermal processing. 
     
     
         9 . The method of  claim 1 , wherein the annealing comprises a high temperature oven process. 
     
     
         10 . The method of  claim 1 , wherein the annealing comprises a laser thermal annealing. 
     
     
         11 . The method of  claim 7 , wherein the rapid thermal processing is carried out at temperatures of 550°C or higher. 
     
     
         12 . The method of  claim 1 , further comprising removing contaminants from the one or more SiC/Ni metal stacks after the annealing. 
     
     
         13 . The method of  claim 12 , further comprising an additional thermal annealing processing after the removing of contaminants. 
     
     
         14 . The method of  claim 1 , further comprising removing unreacted Ni metal from the one or more SiC/Ni metal stacks after the annealing. 
     
     
         15 . The method of  claim 14 , further comprising an additional thermal annealing processing after the removing of unreacted Ni metal. 
     
     
         16 . The method of  claim 1 , further comprising an oxygen plasma processing of the nickel metal contact material. 
     
     
         17 . A method of manufacturing a silicon carbide (SiC) wafer comprising:
 forming a substrate comprising SiC at one or more parts of a surface;   cleaning a surface area of the substrate by a hydrogen plasma atmosphere;   applying nickel metal contact material on the cleaned surface area to form one or more SiC/Ni metal stacks at the one or more parts of the surface; and   annealing the one or more SiC/Ni metal stacks to form one or more Ohmic contacts.   
     
     
         18 . The method of  claim 17 , wherein the cleaning of the surface area is carried out by a hydrogen plasma processing using at least one of a pure hydrogen atmosphere or an atmosphere comprising hydrogen in admixture with at least one of a carrier or inert gas. 
     
     
         19 . A method of manufacturing a silicon carbide (SiC) wafer comprising:
 cleaning a surface area of a substrate by a hydrogen plasma atmosphere;   applying nickel metal contact material on the cleaned surface area to form one or more SiC/Ni metal stacks; and   annealing the one or more SiC/Ni metal stacks to form one or more Ohmic contacts.   
     
     
         20 . The method of  claim 19 , wherein the cleaning of the surface area is carried out by a hydrogen plasma processing using at least one of a pure hydrogen atmosphere or an atmosphere comprising hydrogen in admixture with at least one of a carrier or inert gas.